Rotation mechanism for rock drills



Sept. 7 1926. 1,598,645 C C HANSEN v ROTATION MECHANISM FOR ROCK DRILLS INVENTOR iha lea 8 W 4 H15 ATORNEY Filed Dec. 17, 1925 Patented Sept. 7, 1926.

UNITED STATES 1,598,645 Parent OFFICE.

CHARLES C. HANSEN, OF EASTON, PENNSYLVANIA, ASSIGNOR TO ING-ERSOLL-BAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ROTATION MECHANISM FOR ROCK DBILLS.

Application filed. December This invention relates to rock drills and more particularly to mechanism for rotating the drill steel. 7

One of the objects of the invention is to rotate the drill steel effectively by means of a spirally fluted rifle bar and to release the ratchet mechanism of the rifle bar on the reverse stroke of the hammer piston.

Other objects of the invention will be in part obvious and in partpointed out hereinafter.

The invention will be more clearly under" stood by reference to the drawing, in which Figure 1 is a longitudinal section through a giammer drill embodying the invention, an I Figure 2 is a cross section through the ratchet mechanism of rotating device.

Referring to the drawings, the percussive drill comprises a hammer piston A arranged to reciprocate within a cylinder B adapted to be provided at alternate ends with motive fluid under pressure by means of an oscillating valve 0 operating automatically in a manner well known in the art. The hammer piston A has a nose or shank D for striking against the drill steel E engaged by a chuck F rotatably mounted in a front head Gr supported on the front end of the cylinder B. The drill represented in' the drawing isof the type in which the chuck F is rotated by the piston of which the shank D is fluted. The chuck F is preferably mounted in a sleeve H engaging the chuck F and provided with a fluted nut J within which the splined or fluted shank D of the hammer piston A is adapted to reciprocate and at the same time cause rotation of the chuck F. The rearmost portion of the shank D is preferably cylindrical to form a seal with a Washer K within the cylinder B to prevent leakage of motive fluid from the forward end of the cylinder. The rear end of the cylinder B is inclosed by a back head L.

The rotation mechanism comprises a rifle bar 0 for the piston A extending into the rear end of the cylinder B and having a ratchet head P. A pawl ring Q surrounds the ratchet head P and is adapted to support a plurality of pawls R for engaging the ratchet head P. The teeth of the ratchet P are arranged in a manner so that on the forward or striking stroke of the piston A,

17, 1925. Serial No. 76,111.

the piston A and consequently the drill steel E do not rotate, On the forward stroke the ratchet head P may rotate in a.

clockwise direction, (Figure 2), due to the rifling of the bar U. On the back stroke, however, the pawls R are adapted to engage the ratchet head P and to prevent turning thereof. As a result the. hammer piston A rotates and by means of the chuck F the drill steel E also rotates. The rifle bar 0 is prevented from moving longitudinally of the bore of the cylinder B by a back cylinder washer S having a central bore T through which the rifle bar O extends. At the rear face of the ratchet head P the back head L acts as a thrust bearing to prevent longitudinal movement.

. The pawls R are each provided with a cylindrical bearing end U freely journaled in bores Vin the pawl ring, Q to permit free oscillation of the opposite or. ratchet engaging end.

It will be noted that on the forward stroke of the hammer-piston A rotating the ratchet-head P it is more desirable that the. pawls R be not pressed against the ratchet head since the rubbing together of the surfaces may wear the ends of the pawls. To this end therefore, means is provided to intermittently press the pawls B into engagement with the ratchet head P and at such times only when it is desired that the pawls are in engagement with the ratchet head P. This means is preferably pneumatic and in this embodiment includes plungers W adapted to reciprocate in bores Y in the pawl ring Q, extending generally in the direction of the ratchet head to engage the inner faces of the pawls R. The outer ends of theplungers W are exposed to constant pressure of motive fluid admitted to the bores Y through an annular groove Z in the pawl ring Q, communicating by means of a passage 7) in the pawl ring and the wall of the cylinder 13 with a source of motive fluid at a suitable point such as the interior of the chest 0 for the valve C. Free communication is permitted between the inner ends of the plungers WV and one end, preferably the back end, of the cylinder B. To this end a plurality of holes (Z are bored through the back cylinder washer S permitting the free admission and escape of motive fluid between the rear end of the cylinder B and the space about the ratchet head P. It will be noted that air passing in and out ofthe holes a will carry with it lubricant in suflicient quantity to keep the ratchet head P and associated part-s well oiled.

As the hammer piston A reciprocates the operation of the rotation mechanism will be as follows: On the forward stroke of the hammer piston A motive fluid admitted to the rear end of the cylinder B to drive the piston forward is admitted through the holes 01 into the space about the ratchet head P at substantially the full line pressure. This pressure is exerted against the inner ends of the plungers tending to force the plungers out of engagement with the pawls R. The opposite ends of the plungers are constantly subjected to motive fluid at full line pressure admitted from the interior of the valvechest 0 through the passage 6 and the groove Z to the bores Y. The end faces of the plungers WV are inthis instanceof substantially the same size, therefore the pressures at opposite ends of the plungers balance, allowing the pawls R to move as they will. On this forward stroke of the piston A the engagement of the'fiutes of the rifle bar O with the piston cause the rifle bar and ratchet head P to rotate in a clockwise direction (Figure 2). The pawls B- being released by the plungers N do not press with any substantial force against the ratchet teeth of the head P. On the back stroke of the piston A the motive fluid under pressure has escaped from the back end of the cylinder B through an exhaust port 6 and likewise substantially all of themotive fluid under pressure about ratchet head P has likewise escaped through the holes (5 and to atmosphere through the exhaust port 6. On the back stroke of the piston A, therefore, the plungers W are pressed from behind by motive fluid in the bores Y in turn pressing against the pawls R to engage, the teeth of the ratchet head P. In this manner the pawls R are pressed into engagement with the ratchet head P only on the rotation stroke of the hammer piston A. At other times the pawls R float freely so that relatively little wear is produced by rubbing against the teeth of the ratchet head P.

The drill may be provided at the back head L with a suitable water connection plug 7 associated with a water tube 9 for supplying water to the hollow bore (not shown) of the drill steel E. 1

I claim:

1. A rotation mechanism for percussive drills comprising a rifle bar having a ratchet head, a pawl. ring surrounding said ratchet head having bores to receive plungers, pawls in said pawl ring adapted to be held in engagement with said ratchet head, and plungers in said bores in communication at one end with a source of intermittent pressure, the other ends of said plungers being exposed to a source of constant pressure.

2. A percussive drill comprising a hammer piston, a cylinder for said piston arranged to he provided at alternate ends with motive fluid under pressure, a rifle bar for said piston extending into said cylinder and having a ratchet head, a pawl ring surrounding said ratchet head at one end of said cylinder, pawls in said pawl ring to engage said ratchet head and reciprocatory plunger-s in said pawl ring to hold said pawls in engagement with said ratchet head and exposed at theirinner ends to intermittent pressure from one end of said cylinder and at their outer ends exposed to constant pressure. g 1:" iv

3. A percussive'drill comprising a ham mer piston, a cylinder for said piston arranged to be provided at alternate ends with motive fluid under pressure, a rifle bar for said piston extending into the cylinder and having a ratchet head, a pawl ring surrounding said ratchet head and provided with bores extending generally in the direc tion of said ratchet head, reciprocatory plungers in said bores adapted to be exposed at one end to the intermittent pressure in one end of said cylinder, said cylinder and pawl ring being provided with a passage leading from a source of constant pressure to the bores in said pawl ring to provide constant pressure atthe other end of each of said plungers, andpawls in said pawl ring adapted to be pressed by said plunger-s into engagement with said ratchet head.

In testimony whereof I have signed this specification.

CHARLES C. HANSEN. 

